SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7dcf06a947597f08b7671a058385be83cea52c6f697e60f811967af123f416ff' 
  AND token = 'vMv+6lRcaBb8a54RvWXE2FykzdTR9eu8fR4Q4DaIwBU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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