SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'c1d31a71c7937bf56398bac653ae8d2298ed5a0f6761ae8b7b0ffa37e889e8d9' 
  AND token = 'kZMY/NEwRGYRHWpiVZkGUeyq+osunl5MyA/R4hihKJA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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