SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'fd79dcd8ff080701ecf897ef90870af0a83b7aa67d71891f32861707c7dfe635' 
  AND token = 'NPrD2+27OyxlD2oeeGR3AEHviHPiLsEDXT9XBmL33yg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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