SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'b50d96f0fbe0b6685ae812b9630fcdca1e2e8661c32e8b3e27454801f3575b35' 
  AND token = 'uzrRK6+6tC+4U/zWNwUiEJUwgsZIGdBO8UMHp/xLu5E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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