SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0f7669300472b99c16078250ef75858834c165614d4c13d0991fcbc3b6689983' 
  AND token = 'b2vJ9Rfk9kR9NCW35Tr7thJhp+pdv4GSZLzeG48cUM8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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