SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '4cf3f0a4db4e31c485674b3c539abaade5eb9beb7829dfd9a0c454f898845225' 
  AND token = 'mUJJV8Fec04cMlYpkXr1R70T0BzwCa2uZStFTVe26ck=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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