SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4fc8dcdb640c94fd35892135f964aeebbb060c4d2562bc592fb94da1275045f1' 
  AND token = 'ssQRjqy7SbL2QfgGI9g50xwdyyA1uQyQRLQYrj/mRCs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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