SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '544145dce20f2c7a6c5c2c45979d135a79a49961a0c4951d33164ffa64e298f3' 
  AND token = 'OAFKNjPJNtRrDMv9oSVjG/fuGMhSTB/zwEPquVx/4qs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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