SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a66df8d5d684de345eb3a338537803c7534f567cab7407949449265a9cebcba1' 
  AND token = 'zSHkOkFjaoywWhlHH+KBfb4xuysLCfqwAE4CvhbVyC0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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