SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f51c60c3f5bed7867b5b47edbb20260acb1776d047e4e7c48126250178a40ab8' 
  AND token = 'WJVDNCmLmVOOTkpzAogMfcZDMclSaw36lFZ4STXAWxQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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