SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5ea335a0e5efdf88537c3003305f20c7c34425b5e794ca80bdda10865b12868a' 
  AND token = 'KhDBcHD6lnherIwsWvBhvbts3JX7fYDHarXrfSORRYo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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