SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '187df4d8a94724ae8098b4040209d2bf6b45752d7c6b4ac837855a95b11aac10' 
  AND token = 'Bj3STDte6QPXr6wJFg/WY93EjkXdbas+/H09VkVFkec=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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