SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '016e165e5063ccf389aa39c1999832cdb24eb170a22ff896334be50ab1037a99' 
  AND token = 'jYEwac/q4CZVOobsldiZTAcPP0jebiQFSro6pVo6toI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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