SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b7b1aa84e6a5e11062dcef078042e74635be13fb1b91561b668fe5db413cf8ff' 
  AND token = 'fQDQgIDEXyRZuSwwwUbRUA+TZLv8D2ItwLmFiM7sGZg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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