SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '82e391052255423d2fb49273bd4b3a4fa617ff67aaeff46e9298b94c00dc4d3b' 
  AND token = 'JvMLjn6pPun1ymDgptz1zs3AoV5xDBMNZnDJPpORmPg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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