SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f88c2d2d24de7af002685fe67b9a290fd366380373138963e9ea209960e81013' 
  AND token = 'F8PhoEnfnZpEb8ga1tmeuVBnK6u3GcNyDwQnbvPQq4s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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