SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8085c5871b76601d0ad0dcf6867de41b1290834b3e3c79a05200bc530ec341b2' 
  AND token = 'zJiprsqcHtm+ovbR1vv71LlELH0stNMEmEomRbAn7n4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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