SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8ab51dd0eef0ff924eae5fb81525c16b988d677c58c979174feaac12d9934102' 
  AND token = 'nMCLk7V4qAgUz5mifLXJ2zeMAO+eWB6G4Ku975Uyt/0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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