SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9f8e5ecfd4483cb78f9286ee8d2c8b02598df041886fe57132552d36a85f5a1f' 
  AND token = 'CtYt8N0L1RFCyHO4pAVTucNXAPTwbDLTLzIoah0/bV4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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