SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '50dc0a4d2eb976f1de8d1fb575f4f2d111eb4d89d80fbf47cc1d99fcb2c06a0e' 
  AND token = 'ovJsLr72aNu3J5nH0P2X0srMmBD5rdeKfRdQMdgBNVk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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