SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3df19b8ab14cad5faf29ba8731f545df0ef09d63ac875595c424453f4fb922ff' 
  AND token = 'T8ul9eGPyjYLDvHRHPOIB5+fMfSCiaJIVNICjQN4KrA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00013

JSON explain

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