SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4478304cc45b5f4326fd71eb126508f75f6b42384c0363c234b63d44e2324b84' 
  AND token = '8bQ4eVVujthd+g/eI3HSL6eUdlSaLyXd0aIJElMhayE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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