SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1c3a7f47418b13fed8203e861fe4156035f7db26e4de9e177e92c3fc743cf88f' 
  AND token = 'O3PPqZjsmM9jYZJ7+iZY69pJheCDMm5r3sWGV4K05Qs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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