SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1fab11e514f55b83c25ac6b0321324503853073426172e53d3c7e6f6af123bf2' 
  AND token = '5vbN18sWC3WnLPqLQAq/lK8CBQmcraAEHj0v8Rv9aVs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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