SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f11587ad18204ab4f766cd6c2ee2bcb16997554d8968efc33d240a3473ebeffb' 
  AND token = '7QR8HXkTRLIV+KuCOUhiY2ceX1ZRhHmxjrzwYr/X4cM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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