SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f98225c75f9499fb34b5f802304f33823a36a9879990013cd2466c169bb978c5' 
  AND token = 'y6zrPw6RYTxpzQ9vDhJZgP6RhAP5dB9uCII/HA55ZH4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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