SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '77b81173d876760d74f720317de766597d25eafa98eaba9902c9272bda85cc39' 
  AND token = 'WGvkmsExqEDzbWLUEt3HNvHG3gDtTZb1c46ktD8pYlE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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