SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7817093cc1d6f3374d08e16c75bd066c0eb4f45181eea329ac5da8ff5ac0c984' 
  AND token = '3iFJZ2MiNEG/GuwLY6tfhVv3xz4nwqdwtIAnfaF2Bok=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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