SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3eba5f0a4e533d5f0b4960921971969d36a535962376f6fcd3a9cb25b28e6721' 
  AND token = 'w58JfPvoPOMCrd9uKzImN+OcH2yWTZUbMIIshSmKZps=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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