SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'efebf54fd7d8527a30091e9dd640b937c5af35c7295a1e6ded9248790dcb1a16' 
  AND token = 'pVd1y/aKwMOyxfpu3tEzOCB5b2E0QWi9bRIe4RE5Fco=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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