SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fbd2678f9e1e66b8c9ca98d04178ac539937d7f3081c2652c4a55ed79a6ec631' 
  AND token = 'dpVRREuSHL+cLGNpV9fCBERMHXfFLqBcQOnbkug91Sk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00052

JSON explain

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