SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5c6f34166ebf7befa62e7320a26a3cbf12dde6dd9046d878a96f22fd38f879cd' 
  AND token = 'oPCArVpZihq8UYvHIDu87GXQiLaGSHMhBjfdEOV0UjA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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