SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '37d04851ac9f12081be8273836fa04a0877fba845c24977ba92277b6e0ab3db3' 
  AND token = 'vbxNG6th10HOL/OMvaroPXBc8LeQAVP85CQH+qNGffA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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