SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1e8e4a6ee4cf5db44f2b9aed0639191fc0f39d40159be2a6a210e679de71bfac' 
  AND token = 'z3Dcmr1LoAuKyX248hUOpmkWl5XnAA0l5dWrdL3M0MQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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