SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '37dd6d6965d24581dfdaab322d63675ab5943b173605f20095cf4aec1785120e' 
  AND token = 'B12eU2RWQf2bIuMfIOvXxNszmX5WK20PyJYJ+E8Ovks=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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