SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '89957f4df5a0ea75f0e46a6bff31603a1846cdb4d1a84beface09f388b92d724' 
  AND token = 'iC7XcZjG06oXdMtLFz1SqPqD65ppRV4IrtKYc4MB9Kw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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