SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '288165ef07591200b3dbec4114fc0975fef3f89fd90e05f40b99492729754b54' 
  AND token = '16s+z5VeD6JGdSQIRMn3Xr/q/ILLwUFfBfKHJRFvMYM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}