SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '02b9418ccea07b89bf0341e4ad38e547471a973a2a9de1dd36d4e27924a0f9c6' 
  AND token = 'OVESAPuO+zYMmg4RGbG3xARjqMcyw8DRpNxbvQfghjw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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