SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b78ac6b8a93fee1dc738612b441a22aa2dddb44334fc3f746ba20d28464bc496' 
  AND token = 'nfP/QNv+NDjzM+iYSPgvft5bNyJFe9WQBlXd6R/+9tk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00058

JSON explain

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