SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3a7f8ff049da458e5bb033b886eb164d5a176f920f828c19d61dcd876a3d2c1a' 
  AND token = 'uy5qRK3QZ1VbzLO7rEAbyg9XNd6lH+PQ3YUusKwLsVU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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