SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '27210dacb7dd959b18230eb606c1839f803cc15285edb94e64156f4cdd09426d' 
  AND token = '6boTSVLGmKjL3dpTeVdRQ5te5DY1rysvcYWevcAY8uY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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