SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '393931d5a2a5aab4096ea7247164bf613a1308a0299d43f4ef2e96dfcc672a95' 
  AND token = 'W6iYX7KnWEcrdgmKKMkemprT6wY6uH8kLORs2srBZtY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}