SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '2898a22dd8eb5d192c084c866b0612c8f2f1a40046357c71c750f395f21f5594' 
  AND token = '9CMewjBx2tYpn0Vd68DMrehm3VOBhRwlXuoEXQY+x70=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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