SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ceee0dd29d65db3da0f4839676c4b7f69536ef325255894a814404f216fc713d' 
  AND token = 'cxfVXuP/dsJwmr8O1miYnCL+uL3hCCsArUukKDZsDqs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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