SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e17befedb42f2154c28e2addd4203e8005e4e06f4597296571c8f142871bdaa5' 
  AND token = 'RxnzO/OMHKE288WMEL986c43pLoiRLs0VkrfV+7bkys=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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