SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b4fcc438cd90233b9c0645bedb4f64d97161414c0cd288e3e4d89adcb3ccbf14' 
  AND token = '8qcvTT/hk0on3klIdsWSJqWl752APHLcSooIZTxRjpg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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