SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1c971df550284c6078054c8d457db8268b4d7491602c63628cd5983914167508' 
  AND token = 'EPbO49idecxlHsOSA0vYM0zva9iQeoqJPjZsYU1iP6U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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