SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5484ac55603e30b0a4c65cbaab9c3bf29c737cd31e0adb68d2a7cff53de50eb9' 
  AND token = 'tuCRovg3+MtOQnYSyUYPcLWcPdokqUWhF1uHDkkvC9Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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