SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5b083398bd6630a531a29fdd59550ad2f85275bdff24f0c8d63cbbf621443d00' 
  AND token = 'M/hM2rE7Dejt+gkpePAIOIv5d09DY0N8GPHpsJlUb28=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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