SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4792343cdcbff3abacdd2ae97caf85ab24d3bb39a948ed1531f35cfaa62c2b89' 
  AND token = 'bMJQT80OnptQxQfVQcHIDV3W6yZ0WM4r0x5q8tqz0m0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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