SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '47b83f837fa6244281008461525da923e80868154b9b7d9b74d61ff262fbceaa' 
  AND token = 'eWLEXVeDXKs0zDAHLeuYcX2C+ccdZqfzcQzgt+p6gC0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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