SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7cc8157a49cce94224d2c80c17171eb1be50f676cc790e53daff2591b67264e4' 
  AND token = 'VOJI/h9xQcqJUDvBKByuUL2h0LaF+OpCCwBm2vuq9nc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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