SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1fa344a303b4228b510fbc0a2d55698b300ee3ee12550812354f25c556245348' 
  AND token = '5ViPjzheO9YGVw+omhFVa6WvNV3qzaLL9/vJVXaZkAE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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