SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '825ff2982b23d8725a40a67aff1d611837158e96e14b22dae90278491e2a7986' 
  AND token = 'DgKhVYXWmAzXeKDDIiCziXxMlnU14+dmzoy5JwRRSGc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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