SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cb037d94edba6077f1945f022af16fd04978cb34dbc4f6e2d9fdef94ba00e514' 
  AND token = 'WmhP9D3FsgK8++7MQxVqcfj9wh7cZV8B1z7HHTVPAts=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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