SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1451fd996fecbcce01b5add333fea6161c54d6ba2a26804f9aec5c8cb90319e5' 
  AND token = 'kHgDFVC2TIV7uRvQidfTqdhsB/eg8Gj0dngtFuLLbuM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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