SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e8457bca7eacc7661bb4df98f0879dc81e13d1e8218645ae08ddf19870afbf96' 
  AND token = 'M1C4j3s3v9v3lxy0Nft3T+jjJFrl9LixjTCxobhY7Xw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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