SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'b0c1d17141188c7268a18e36f74a6b57d09c2f92e562191216d6942e0d2ea5a5' 
  AND token = 'HAvyXLndjFsItvPknQTfPc6R1/tuG53pCjhBslUcCf0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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