SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd74fcecd9d356011a1a277b4e80cc78cde1c096635034edb9504f2750afa28d1' 
  AND token = 'j/phaydDo3zmdquVznQ6RZJXKzKXNyWxFnIlUEtrSEw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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