SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '338c283afabcd394531bc4ecdabd1c1ed85995208bfa4a05436f9dbccd747a91' 
  AND token = '2qeCt7e36VKonYL9eQkmICcH74zVeoioKpEySoXNL98=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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