SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'd1b91787d2ecb0e9df0517d91a5ef6040f5f1cd5d592385d44ef36e67509bcf2' 
  AND token = 'tNKv75/VfGbItfzhASEs1P+ZTQ9BZuyMlgdTVH3hYk0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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