SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '6d2d6fcb708e80a2ff3d929026b2878bb1f3e755fc6b3669a7a070883cd9bb8b' 
  AND token = 'GH379QLohq3XSVYym/YplW4qlVy9d7/vkuP1kydBnxY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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