SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f3ee626acf9f5d29d8c61b63d1c6885124caf04e51ebf656923a8756c75b108d' 
  AND token = 'A/M3lI8uFY6kQDLgUDRVXE6qhY7PlRh+5yQKQk+aBWw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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