SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f5c314e0c01b75a8501ca71acd09a76ffd3f6500009898e44abe080c163a6aed' 
  AND token = 'n5PyOi75phGbbsdreuV7y5Mu2X3Htl7LESJhyZJibww=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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