SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a54b4d1a44c2daeeb1541621a56a6125a964eab5cff285718de31ff6a2030d3d' 
  AND token = 'jfu8sfXZEMxwqYWB9hgyQGwLAOo0/ciOvkMNvjXKmYU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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