SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8e49c4fa1e43e9605d3c7e9362b6707b971985695c116955f1247c25ee9350f9' 
  AND token = 'nk9+lHid8k7ZD6qeYvmvS/Lg84KG8dQ5Jw9WFYMLE+s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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