SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b54f386e238add30b8fb014503daf20e8fa31149254560d904886f74f4ed497f' 
  AND token = 'QBMYEQK7X3pPoblKJt6KGcQj54v+1O/8TVp2C5Ldhh4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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