SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '75421a9e6a2eefeec75eaa4f31439bbd80c7b102b011fd7b3f4b6e1ebd982e16' 
  AND token = 'MZb9+Jvzlte9sxBZRYTGNYiW+HfMIbKl6C8PKR6hrV0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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