SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'ed8d876dff4de799fa8f4fa3e2c5a225b14909fb5d8928578dd0f1852f4597f7' 
  AND token = 'jzhSOIZ/XGwRM5+fsP3yBJVmGAkc2sugnIzaTnvoIu4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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