SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd5b771a3988ab0ef047eb27c1ba2f426ee0fd729c08f6880b0115ba03751dfd6' 
  AND token = 'Ea5KmPjKBkhNbvKmlhcDXTrLppcFtFviFtBe5zUFzEI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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