SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'da6eca50797ba8445ddec3df500f0e9afa587eb85e3afb010fdc69f727d25588' 
  AND token = 'hmlaJfrazn1XQAomAvS4WAypYirazUWwq2Z5UgWFvRE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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