SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '985fb7f1984f050f73ab8ff62553faaaa523d6e0dbbc91c4c442a5e18181802e' 
  AND token = '27xW6fU1k/qkC8/+skZ+YGJTZqpKumSy2QEgDbQpZwQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00051

JSON explain

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