SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7adbb727ca58225befd49860df636bf19749b49b0c591727ea04c4f1b5f3fb80' 
  AND token = 'lsxVX575zsp1LFYv7UGkBYnjBMdmwFT+7pNKiNRGIRo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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