SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f73fb0391981815342121932f77e766cc5b8a1e161fd3888ba3d87fb77857acd' 
  AND token = 'qILBXJcgEn7CJw/x0O0BVgI07BV53LMcAVcuxvQGisk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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