SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7c10513008f34df800d98d30e9a74c89086a41979f1c2f578a31381cddf8b708' 
  AND token = 'bS5nY8qguO/PPyEFAt6uyXEy4bri0b+xQne7PYjfsnw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}