SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f6571d0978d6816b79f31be87674cb3ccd2dd21ec3384bdf4b7fe28393061a90' 
  AND token = 'j9Rajh3mEKrL4ZexV/zZmKMEG88J4Hpmy5HiP/g4ZJ0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}