SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'db55ec0db9b69bdc851a4aeabb0891d396bdd1ce17be645ac7f2905f2cbc5f67' 
  AND token = 'YpB5ULj0NdGSZyNdJT27yhlgiY1nm7KvGDaWwgz71cg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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